Question: Express your answer as a mixed number simplified to lowest terms. $3\dfrac{11}{20}-1\dfrac{4}{5} = {?}$
Answer: Find a common denominator for the fractions: $= {3\dfrac{11}{20}}-{1\dfrac{16}{20}}$ Convert ${3\dfrac{11}{20}}$ to ${2 + \dfrac{20}{20} + \dfrac{11}{20}}$ So the problem becomes: ${2\dfrac{31}{20}}-{1\dfrac{16}{20}}$ Separate the whole numbers from the fractional parts: $= {2} + {\dfrac{31}{20}} - {1} - {\dfrac{16}{20}}$ Bring the whole numbers together and the fractions together: $= {2} - {1} + {\dfrac{31}{20}} - {\dfrac{16}{20}}$ Subtract the whole numbers: $=1 + {\dfrac{31}{20}} - {\dfrac{16}{20}}$ Subtract the fractions: $= 1+\dfrac{15}{20}$ Combine the whole and fractional parts into a mixed number: $= 1\dfrac{15}{20}$ Simplify to lowest terms: $= 1\dfrac{3}{4}$